Charles Ellicott Commentary Acts 13:9

"But Saul, who is also [called] Paul, filled with the Holy Spirit, fastened his eyes on him," — Acts 13:9 (ASV)

Then Saul (who also is called Paul): It is impossible not to connect the mention, and probably the assumption, of the new name with the conversion of the proconsul. It presented many advantages:

1. It was sufficiently like his own name in sound to fall within the general practice that turned Jesus into Jason, Hillel into Pollio, and Silas into Silvanus.
2. It was a Roman, not a Greek, name, and as such, it aligned with the ultimate work of the Apostle—already, perhaps, contemplated in thought ()—of bearing his witness to Christ in the imperial city.
3. It formed a link between him and the illustrious convert he had just made.

He was, as it were, claiming a brotherhood with him. From this point of view, it is interesting to compare the name of Lucas or Lucanus, as borne by both the evangelist and the poet. (Compare to Introduction to St. Luke, Vol. I., p. 237.) Other reasons that have been assigned—such as (1) that the Greek word Saulos had a disgraceful meaning, like 'wanton,' or (2) that the meaning of Paulus, 'little,' commended itself to the Apostle’s humility—may be dismissed as more or less fantastic.

Filled with the Holy Ghost: The tense of the Greek participle implies a sudden surge of spiritual power, showing itself at once in insight into character, righteous indignation, and foresight of the divine chastisement.

Set his eyes on him: The word is one already so often noted, as in Acts 1:10 and elsewhere. As applied to St. Paul, it may possibly connect with the defect of vision that remained as an after-effect of the brightness seen on the way to Damascus. The Greek word, however, it is right to add, may just as well express the fixed gaze of men with strong powers of sight as that of those who suffer from some infirmity. (Acts 3:4; Luke 4:20; Luke 22:56.)